Aircraft control apparatus



Aug. 23, 1932. l H HAAS 1,873,579

AIRCRAFVT CONTROL APPARATUS Filed may 4, 1351 2 'sheets-sheet 1 TigLAHPLIFIER I" INVENTOR Harold Haas.

Allg. 23, H. HAAS I AIRCRAFT coNTRoLVAPPARATUs Filed May 4, 1931 2sheets-sheet 2 AMPLIFIER 20 ating sai 'Patented yAug@ 23, 41932 UNITEDSTATES. PATENT OFFICE HAROLD HAAB, 0F ARLINGTON, NEW JERSEY, ASSIGN'OB.T0' lBJFZNDIX RESEARCH COB- l PORATION, or EAST ORANGE, Naw sanear, ACORPORATION. or INDIANA AImArT CONTROL APPARATUS Application ma my 4,m1. semi No.: 535,052.

i The present invention relates to naviga- 4 tional controla paratus andmore particularly to means Or'maintaining the stability of'a mobileobject.

s. One of the objects Of the invention is to provide novel means forcontrolling and maintaining the stability of a mobile object about anyone or all of its three axes;

Another Objectis to provide novel means lowhereby a mobile Object, asfor example a ship or aircraft, is maintained on a predetermined path orcourse.

Another object is to rovide novel electrica'l means whereby amo ileVobject is returned 1li` to a predetermined'path or course when itdepartsftherefrom.

v Another ob 'ect is to provide in combination with a control member ofamobile object for controlling thelatter, and means for actucontrolmember,l novel means adapted to be energized upon motion of the v mobile'object aboutone of its axes for rendering said actuating meansoperative, whereby sald ob'eot is returned tonormal position.

` 2,5. Anot er Object of the invention is to provide in combinationwitha control member of a mobile object for controlling the stabilityofthe latterwith respect to one of its axes, novel electrical apparatusincluding light 9 responsive means and means for actuating the control`member upon energization of said light re onsive means when said Ob'ect is disturbe about the axis about which it 1s controlled, wherebythe object is restored to nor- -al fmal position.

A further object is to provide novel electrical apparatus includinglight responsive means for operating electrical circuits in ac-`cordance with the angular deviation of a ,mobile object carrying saidapparatus from apredetermined path or'course whereby said object isreturned to said path or course.

lAnother object lis to provide a novel elec- 45 trical control systemfor maintaining a mobileobject on a predetermined path or course,

- .Y rfvhich system is so designed as to.depend for oPr'atonuPOn anelectric current produced by changes in relative osition4 between adilthe ectrical circuit arrangementof one em- 50 rectional device landhghtresponsive means views,

due toa deviation of the mobile object from its predetermined path orcourse.

Another Object of the invention is to pro- -vide in combination with adirectional or controlling device such as a magnetic compass a novelelectrical control lsystem including light responsive means formaintaining .a mobile ObJeot, on which the directional device ismounted, on a predetermined path or course and adapted tobe operatedupon relative angular movement'between the directional device and themobileobj ect, whereby the latter is returned to its path or course.

A still further object is to rovide in combination with a control mem erof a mobile object and a directional device carried by the latter,apparatus including light responsive means trol member when the anobileobject deviates from'ea predetermined path or course, and

novel means for `returning the control memor causin actuation of theconber to its initial position after the mobile objecthas returned toits predetermined course, whereby Over-swinging of the mobile object isprevented.

Still anotherobject is to provide in combination with a mobile object,means responsive to the inclination of said object from a levelcondition, and novel means cooperating with and rendered effective bsaid last mentioned means upon such inc 'nation of said "mobile objectfor restoring the level condition The above and other objects andadvantages of the invention will appear more fully hereinafter from aconsideration of the detailed description which follows, taken together`with the aocompan ing drawings wherein two embodiments o areillustrated. It is to be expressly understood, however, that the drawins arel for the pur ose of illustration and esoription lonly an .are notdesigned as a definition of the limits of the invention, reference beinghad lfor this purpose to the appended claims.

In the drawings, wherein like reference charactersV refer to like partsin the two Fi .lis 'a diagrammatioview illustrating the invention ad pabodiment of the invention as employed for directional stabilization of amobile object; and

' Fig. 2 is similar to that of Fig. 1 illustrating another embodiment ofthe invention as ein loyed for stabilization of an aircraft about itstransverse axis.

The' apparatus embodying the present 1 nvention, when employed tomaintain a mobile object on a predetermined course, comprises adirectional device, such as for example a magnetic compass'adapted to becarried by the mobile object which is to be maintained on apredetermined path or course, means for o erating a control member ofthe mobile o ject, as for example the rudder thereof, means effectiveupon relative movement between the directional device and the mobileobject for causing energization of the control mobile object is returnedtoits course, and means for restoring 'the control member or rudder toits initial positionafter the mobile object has returned to its course,whereby over-swinging is prevented.

Referring to Fig. 1 of the. drawings, in the form shown therein, theapparatus comprises a turn responsive or directional device 3 which inthe present instance is shown as a magnetic compass, althougha-gyroscopic turn indicator maybe employed in the place thereof. Thecompass is constituted by a circular frame 4'mounted on a support 5which is adapted to be secured to and moved -with the mobile objectwhich is to be controlled. Pivotally mounted in the frame 4 is adirectional element 6, as for example a ma netic compass needle whichhas its north en enlar ed, as indicated at 7, for a purpose which wi lappear more fully hereinafter. The bottom of the frame 4 is cut out toform a. circular disc 8, the latter being arranged to be rotatablyadjusted relative to the frame 4 by means of a rod 9 to which the discis secured. The rod 9 is carriedby a bracket 10 'ustably secured to thesupport 5 and cale of rotation through 360 degrees about the latter byloosening the set screw 10a.

Novel means are provided whereby upon deviation of the mobile objectfrom a redetermined path or course, a control mem r of said object, suchas the rudder 11, is arranged to be actuated to return the object tosaid course and includes a light res onsive or photo-electric systemwhich is ren ered effective upon such deviation to control said rudder.n the form shown, the means last referred to comprise a pair of seleniumor photo-electric cells 12 and'13 which are carried by an arm 14 securedto or formed integral with the bracket 10, and which projects under theframe 4 so that the selenium cells are directly below a pair ofapertures or slits 15 and 16 formed in the disc 8 near its periphery. Asource of light 17, as for. example member actuating means whereby thevuntil the source of light 17 and the apertures 12 and 13 are in aposition corresponding to the compass direction in which it is desiredto pilot the mobile object.

The source of light 17 is arranged to be energized from the lowpotential side of a double voltage generator 18 through the electricalconductors 19 and 2O and connected to said li ht source in any suitablemanner (not shown Athrough the support 5 andbracket .10. The selenium orphoto-electric cells 12 and 13 are normally inoperative but arranged sothat upon deviation of the mobile object to the left, for example, theslit or aperture 16 will be uncovered first, thereby energizing the cell12, and upon a deviation ofthe mobile object to the ri ht, the aperture15 will be uncovered first, t ereby energizing the cell 13. y Uponenergization of either of the selenium cells, an electric current iscaused to flow, as is well known in the art, and which may be ampliied bsuitable electric amplifiers 21 an 22, eacA of which is connected to theselenium cells by means of conductors 23, 24, and 25, 26 respectively.The amplifiers are preferably of the vacuum tube type, the tubes ofwhich are supplied with suitable plate potentials from the highpotential side of the generator 18 by means of the leads 27 and 28. Thecathodes of the vacuum tubes of each of the amplifiers are arranged tobe heated by current from the low potential side of the generator 18 andfor this reason are connect- Ved to the leads 19 and 20 by means of theleads 29 30, and 31, 32.

Means are now provided whereby upon energization of one of thephoto-electric cells, the control member of rudder 11 of the mobileobject is arranged to be actuated in one direction, and uponenergization of the other photo-electric cell, said rudder is actuatedin the opposite direction. Invthe embodiment illustrated, said meanscomprise an electric motor 33 adapted to be drivably connected toa gearwheel 34 by means of a double Bendix drive which is constituted bypinionsy 35 and 36 which arel arranged to be moved longitudinally alongthe shaft 37. Pinions 35 and 36 are threaded on the shaft 37 in such amanner` that when the motor armature rotates in one direction, pinion 35will mesh with the gear 34, and when rotated `closed electrical in theopposite direction pinion 36 will mesh with'the gear 34. f y 4 Motor 33is adapted. to be energized lfroma suitable 'source of electrical eneras for ex,- ample a battery 38 throu h a fie d reversing relay 39, theoperation o which will appear hereafter. Energization of the electricmotor 33 is yaccomplished by means of a pair of relays 40 and 41 whichinclude solenoid windings 42 and 43 respectively. Associated with thewinding 42 are a pair of normally contacts 44 and 45 and a pairofnormally open contacts 46 and 47, land associated with the winding 43is a similar pair) of normally closed contacts 48 and. 49 and two Apairof normally open contacts 50, 51 and 52,

53. Contacts 44 and 45 are connected in series with the winding 43 andthe output of the amplifier 22, while contacts 48 and 49 are connectedin series with the winding 42 and the output of the amplifier 21.Contacts 46 and 50 are connected to the armature of the motor 33 throughlead 54 and to the field reversin relay through the lead 55. Contacts47an 51 are connected to one terminal of the source 38 while the -otherterminal of the latter is connected to the other terminal of thearmature and to the fieldl of the motor through the reverse current ofthe lead 56and leads 57 and 58.

52 and 53 are connected in series with a winding 59 ofthe fieldreversing relay 39 and the source 38 by means of the leads- 60, 56 and61. The battery 38 may be charged by' means of a generator 62 which may`be driven by any suitable prime mover, as for example a wind motor oran internal combustion engine when v the apparatus is employedv on anaircraft, or by an electric motor when employed on a ship.

The generator 18 may also be operated in theclosed and currerit from thesource 3 8 flows through the field of the motor- 33 in one direction,but when the winding 59 is de-energized. as when the relay 43 isinoperative, al

spring (not shown) closes the opposite pair of contacts of the relay sothatcurrent from the source 38 ,Hows throughthe motor 33 vin theopposite direction.

' thereby producing a current flow through the It `will be apparent fromthe: foregoing* circuit arrangement, that upon deviation of the mobileobject to the left, forexample. the photo-electric cell 12 will becomeenergized amplifier 21 and the current thus amplified will energizethewinding 42 ofthe relay 40. Upon energization of the winding`42, con

. tacts 46 and 47 which are normally open, are

Y lthen closed, and contacts 44 and 45vwhich are normally closed, areopened. The opening of the latter ,pair of contacts renders the solenoid43 in eective,y and the closing of the conrelay 39 means ontacts of hothe tacts 46 and47 causes energization of thelmotor 33 through the fieldreversing relay 39, whereupon' the motor is rotated in one directionthereby meshing the pinion 35 with the gear 34 which in turn actuatesthev rudr-el'ectric cells 12 and 13 are energized, the current producedbv the one which is uncovered last will be ineiiective by virtue of thefact that the relay winding 43 is open circuited by lthe opening of thecontacts 44 and45 due to the energization of the Winding 42 which isenergized ahead of the winding 43 because 'of the photo-electric cell 12being energized prior to the photo-electric cell 13.` On the other hand,if the mobile object deviates'to the right, then the cell 13 Will beuncovered first and the electric current produced thereby willbeaniplified in the amplifier 22 and cause the energization of thewinding 43 of therelay 41. Upon cnergization ofthe latter winding,contacts 48 and 49 will be opened therebyrendering relay Winding 42ineffective and contacts 50, 51 and 52, 53 will be closed. Upon closingof-contacts 52 and 53,

vrelay Winding 59 Will become energized,

thereby actuating the field reversing relay 39 so that-'the flow ofcurrent through the field ofthe motor 33 will be inthe oppositedirection to produce reverse rotation of said Y motor When 'contacts 50and 51 are --close'd simultaneously with contacts 52 and 53.

Since the motor armature 33 is rotated Ain a `direction opposite .to`that in which it was moved when the mobile object deviated to the left,the pinion36 will now'mesh with the los gear 34, therebyl actuating therudder 11 in the opposite direction to bring the mobile ob'- ject Vbackon its course.

Novel means are also' provided for returningthe control member or rudder11 to norand which is constituted by a pair of spacedW parallel arms63jand 64, thef ends of which are connected together by means of a pairof compression'springs 65 and 66. 4The shaft 62 is.. secured to orformed integral withfthe arm 63,l while the arm'64 is adjustably securedto 'mal position after themobilejobject has rcthe mobile objectV in anysuitable manner, as by means of a lstub shaft 67 and arranged to beadjusted by moving the arm 68 about the shaft 67 and locking tion bymeans ofa throu lithe arm 68'into any one of a series Fes70. It vwill beapparentv that' when gear 34 is actuated to movethe rudder 11 ineitherdirection,l the shaft-'62vl will rotate with the gear, Atherebyrotating th'e arm 63 1t in the adjusted posi-y pin'69 arranged to pass25 so that one of the springs 65 and 66 is compressed while the other isput under tension ecause of the fixed position of the arm 64. As soon asthe mobile object returns to its course, the enlarged portion 7 of thecompass needle 6 covers both of the' apertures 15 and 16, therebyrendering both photo-electric cells ineffective and also the motor 33.When the motor 33 ceases to operatethe pinions 35 and 36 are disengagedfrom the gear 34 in the usual manner of a Bendix drive, and the springs65 and 66 cause the arm 63 to return to normal position which in turnrestores the control member or rudder 11 to normal posiother embodimentof the invention in which the electrical circuit arrangement isidentical with that shown in Fig. 1 except that the apparatus isarranged to be rendered operative in response to lon itudinalinclinations of the mobile object an particularly adapted for use onaircraft. In the form illustrated in this embodiment, the photo-electriccells 12 and 13 are arranged to be energized by means of a lightbeamprojected from source 17 and reflected by means of a pendulouslysuspended mirrored surface 71 which is pivotally mounted in jeweledbearings 72 and 73 carried by frame 74 mounted on a support 75 which issecured to the aircraft in such a manner that the mirrored surface 71will be inclined relative to photo-electric cells 12 and 13 upon aninclination of the craft lupward or downward. It is apparent from thisarrangement that upon a downward inclination of the craft the mirroredsurface 71 will swing into such a position that the light beam from thesource 17 will be reflected onto the cell 12 and upon an upwardinclination of the craft, said light beam will be reflected on to thecell 13 so that a horizontal rudder 76 will be actuated up or down torestore the craft to level flight. The operation of the electricalsystem is the same as that of the system shown in Fig. 1, i. e., whenone cell is energized, the horizontal rudder 76 will be actuated in onedirection, and when the other cell is energized, the rudder 76 will beactuated in the opposite direction.

If it be desired-to control the lateral inclination of aircraft, thependulously supported mirrored surface 71 may be mounted with its axisof suspension parallel to the longitudinal axis of the craft so thatsaid surface may swing relative to the craft when the latter inclines tothe left or to the right, i; e., when the plane is banking. The electricmotor 33 may then be connected in any suitable mannerfto actuate theailerons of the plane for restorin the latter to level Hight.

Although for 'te sake of simplicity, the mirror 71 is shown as a'simplependulum, it

' is obvious that the mirror may be mounted on the frame of agyroscopically stabilized pendulum, whereby acceleration forces arerendered ineffective when the device is employed on an aircrafttraveling at high speeds.

There is thus provided novel apparatus and a novel control system forcontrolllng and maintaining the stability of a mobile object, as forexample an aircraft, about any one or all of its axes in response to themotion of the object about said axes produced by external disturbingforces. There is also provided a novel device for restoring a controlmember of the mobile object to 1ts normal position after the object hasbene stabilized and which is particularly useful in main` taining themobile object on a predetermined path or course. A

The directional or turn responsive device, as for example, the compassor the pendulously suspended mirror, may be mounted in any convenientlocation on a ship or aircraft while the servo-motor may be convenientlymounted in the vicinity of the mem` ber which it is adapted to control.

While only two embodiments of the invention have been illustrated anddescribed, otherchanges and modifications, which will now appear tothose skilled in the art, may be made without departing from the scopeof the invention. For example, the apertures or slits 15 and 16 may beso located in the adjustable` disc 8 that the directional element 6 isdirectly between them, thereby exposing both slits to the light sourcethus maintaining both cells energized when the mobile object is on itscourse.` In such an arrangement, th relays 40 and 41 will be energizedsimultaneously. By properly arranging the contacts 46 and 47, and thecontacts 50, 51 and 5.2, 53, the circuit of the motor 33 may beenergized to rotate the latter in one direction or the other when eitherone or the other of the cell's 12 and 13 is deenergized upon relativemotion between the directional element 6 and the frame 4. Reference istherefore to be had to the appended claims for a definition of thelimits of the invention.

What is claimed is:

1. Apparatus for maintaining a mobile object on a predetermined path orcourse, comprising in combination a direction responsive device carriedby said mobile object and arranged forangular motion relative theretoupon a deviation of said object from-said course, a control member alsocarried by said mobile object, means for actuating said control member,a pair of photo-electric cells `Lavaur/a an electric current upondeviation of -said mobile object from its course, an electrical circuitarrangement including said photoelectric means, said control memberactuating means, current amplifying means for each of said photoelectriccells 'and interconnected relays forenergizing the control memberactuating means so that the latter may move the control member in onedirection or the other upon energization of one or the other of thephoto-electric cells respectively, means connecting said relays in sucha manner that when one is rendered operative ahead of the other, thelatter is simultaneouslyrendered inoperative, and means for returningthe control member` to its normal position after it has been actuated toreturn the mobile object to its course, whereby overswinging of saidobject isprevented.

` 2. Apparatus for maintaining an aircraft' in level flight v.comprisingin combination, a control member carried by said craft, a pendulouslysupported mirror carried by said craft and responsive to the inclinationof the latter about one of its axes, a light source associated with saidmirror for directing a ray of light thereon, a pair of photo-electriccells disposed opposite the mirror, whereby the light ray is reflectedonto'one or the other of'said cells upon the inclination of said craftin one direction or the other so that an electric current isproduced,means connected to each of said cells for.

amplifying said current. means adapted to be energized by said amplifiedcurrent, means tion for counter-balancing the effect of wind foractuating said control member, and a source of/electrical energyforenergizing` said actuating means, said second-mentioned means comprisinga pair of relays arranged' so that when one is energized first by itsassociated cell, the other is rendered inopf erative whereby operationof bothrelays is prevented in the event that the second cell isenergized whilethe first cell is operating.

3. Apparatus for maintaining an aircraft inl level flight comprising incombination, a control member carried by said craft, a pendulouslysupported mirror carried by said craft and responsive to the inclinationof the latter about one of vits axes, a light source associated withsaid mirror for directing a ray of light thereon,l a pair ofphoto-electric cells disposed opposite the mirror, whereby the light rayis reflected onto one or the other of said cells upon the inclina-r tionof said craft in one direction or the otherfso that an electric currentis produced, means connected to each of said cells vfor amplifying saidcurrent, means adapted to be energized by said amplified current,-

means for actuating said control member, a source of electrical energyfor energizing said actuating means,

said second mentioned means comprising apair of relays arranged so thatwhen one is energized first by its associated cell, the other isrendered inoperative whereby operation of both relays is revented in theevent that the second cel is lenergized while the first cell isoperating, and means effective upon restoration of they aircraft tolevel flight for returning the control member to its normal position.

4. Apparatus for maintaining an aircraft in level flight comprising incombination, a control member carried by said craft, a pendulouslysupported mirror carried by said craft and responsive to the inclinationof the latter about one of its axes, a light source associated with saidmirror for directin a ray of light thereon, la pair of photo-electriccells disposed opposite the mirror, whereby the light ray is reflectedonto one or the other of said cells upon the inclination of said craftin onel direction or the other so that an electric current is produced,means connected to each of said cells for amplifying said current, means.for actuating said control member, a source of electrical energy forenergizing said actuating means, said second-mentioned means comprisinga pair of relays arranged so thatv when one is energized first by itsassociated cell, the other is rendered inoperative whereby operation ofboth relays is prevented in the event that the second cell is energizedwhile the first cell is operating, and means effective upon restorationof the aircraft to levelflight for returning the control member to itsnormal position, said last mentioned .means including means foradjusting the control member to a predetermined normal posidrift uponsaid craft.

5. In apparatus for maintaining a mobile object on a predetermined pathor course, the f combination 'of a source of light, a pair ofphoto-electric cells, a directional device carried by said mobile objectand including a plate'interposed between the photo-electric cells andthe light source and having a pair of lbut arranged to uncover one orthe other of said apertures upon deviation of said object from saidcourse so that one or the other of said cells becomes energized. a.control member carried by said mobile object, means as s ociated with.said control member for actul ating the latter in one direction or theother uppn energization of one or the other of said photo-electriccells, and means for returning said control member to normal positionwhen the photo-electric cells are rendered inoperavtive upon the returnof the-mobile object to its course.

6. In apparatus for maintaining a mobile .mi

object on a predetermined path or course, the combination of a source oflight, a pair of photo-electric cells, a direction-responsive de vicecarried by said mobile object and including a plate having a pair ofapertures associated with said cells, said plate being interposedbetween the light source and sai photo-electric cells, and an angularlymovable member arranged to normally cover both of said apertures whenthe mobile object is on said predetermined course but to uncover one orthe other of said apertures when said object deviates in one directionorthe other from said cou'rse, a control member carried by said mobileobject, means for actuating said control member, an electrical circuitarrangement including said photo-electric cells and said actuating meansand rendered operative upon energization of one or the other of saidphoto-electric cells for operating said actuating means so that thecontrol member is moved into such a position as to return themobilevobject to its predetermined course, a pair of'relays alsoincluded in said circuit, means interconnecting said relays in such amanner that when one becomes operative ahead of the other the latter issimultaneously rendered inoperative, and means eliective to restore thecontrol member to its normal position after the objecthas returned toits course.

7. Apparatus for controlling the stability of a mobile object withrespect to one of its aXes comprising, in combination, means responsiveto the motion of said mobile object about said axis, a source of light,a pair of photo-electric cells associated with said light source andsaid motion-responsive means so that one or the other of said cellsbecomes energized, a control member carried by said mobile object, meansfor actuating said control member, an electrical circuit arrangementincluding said photo-electric cells, said actuating means and a pair ofrelays for energizing said actuating means so that the latter may movethe control member in one direction or the other upon energization ofone or the other of the photo-electric cells, respectively, meansconnecting said relays in such a manner that when one is renderedoperative ahead of\the other the latter is simul taneously renderedinoperative, and means for returning the control member to its normalposition after it has been actuated to return the mobile object to itscourse.

8. Apparatus for controlling the stability of a mobile object withrespect to one of its axes comprising, in combination, means responsiveto the motion of said mobile object about said axis, a source of light,a pair of photo-electric cells associated with said light source andsaid motion-responsive means so that one or the other of said cellsbecomes energized, a control member carried by said mobile object, meansfor actuating said control member, an electrical circuit arrangementincluding said photo-electric cells, said actuating means and a pair ofrelays for energizing said actuating means so that the latter may movethe control member in one direction or the other. upon energization ofone or the d other of the photo-electric cells, respectively,

means connecting said relays in such a manner that when one is renderedoperative ahead of the other the latter is simultaneously renderedinoperative, and means for returning the control member to its normalposition after it has been actuated to return the mobile object to itscourse, said last mentioned means including means for adjusting thecontrol member to a predetermined normal position for counter-balancingthe effeet of wind drift upon said mobile object.

9. Apparatus for controlling the stability of a mobile object withrespect to one of its axes, comprising in combination, means resonsiveto the motion lof said mobile object a out said axis, a source of light,a pair of photo-electric cells associated 'with said light source andsaid motion-responsive means so that one or the other of said cellsbecomes energized, a control member carried by said mobile object, meansfor actuating said control membr upon energization o said cells, and anelectrical circuit arrangement including said photo-electric cells, saidactuating means and means interconnecting said cells and said actuatingmeans in such a manner that when one cell is energized the other isrendered ineffective. 5

10. Apparatus for controlling the stability of a mobile object withrespect to one of its axes, comprising in combination, means responsiveto the motion of said mobile object about said axis, a source oflight,'a pair of photo-electric cells associated with said light sourceand said motion-responsive meansso that one or the other of said cellsbecomes energized, a control member carried by said mobile ob 'ect,means for actuating said control mem r upon energization of said cells,an electrical circuit arrangement including said photo-electric cells,said actuating means and means interconnecting said cells and saidactuating means in such a manner that when one cell is energized theother is rendered ineective, and means for returning the control memberto its normal position after it has been actuated.

In testimony whereof I have signed this specification.

HAROLD HAAS.

